A new study suggests that speech involves the use of both sides of the brain, overturning a widely-held belief that only one side of the brain is responsible for the task.
Researchers at New York University implanted specialized electrodes inside and on the surface of the brain of 16 volunteers with epilepsy to map their brain activity. The volunteers were then told to repeat nonsense words to trigger brain activity and allow the researchers to isolate speech from language. They found that the participants used both sides of the brain for speech.
"We asked the patients to listen and speak to different cues, different words, and then we monitored their brain activity and we found it was present on both sides of their brain in equal ways," Bijan Pesaran, an associate professor in NYU's Center for Neural Science and the study's senior author, said. "It really made no difference what side of the brain we looked at. It was equally strong."
It was long believed that one side of the brain controls speech i.e listening and speaking, and the other side controls language (constructing and understanding of sentences) but the findings of the study suggest otherwise.
"Our findings upend what has been universally accepted in the scientific community -- that we use only one side of our brains for speech," Pesaran said. "In addition, now that we have a firmer understanding of how speech is generated, our work toward finding remedies for speech afflictions is much better informed."
The findings of the study, which were published in the journal Nature, are seen to improve understanding of how speech is generated in the brain and could provide leads to new ways of treating speech-related problems.
"Now that we have greater insights into the connection between the brain and speech, we can begin to develop new ways to aid those trying to regain the ability to speak after a stroke or injuries resulting in brain damage," Pesaran said. "With this greater understanding of the speech process, we can retool rehabilitation methods in ways that isolate speech recovery and that don't involve language."
